The present invention pertains to a two-joint arrangement for the articulated connection of guide elements, preferably of a motor vehicle steering linkage with a common articulated part.
Such two-joint arrangements have become known, e.g., in the steering linkages for motor vehicles. The guide elements in this case are, on the one hand, the steering rod connected to a steering gear, and, on the other hand, the steering tie rod that is used for connecting two pivotable wheel carriers. The steering tie rod and the steering rod are each fastened to one of the wheel carriers to be pivoted synchronously in an articulated part designated as a drag bearing via a ball-and-socket joint. Such two-joint arrangements are very compact, but often form an inseparable connection of the joints, so that in case of the wear of one joint, the entire two-joint arrangement must be replaced.
In order to remedy this drawback, a joint connection with two ball-and-socket joints is disclosed in DE 40 11 179 A1, for example, from the state of the art, in which, to obtain a separable embodiment requiring little space for components, the joint arrangement is designed such that the first joint with a joint pivot is inserted into a continuous recess of the articulated part, whereby the joint pivot has a threaded section. A joint part of the second joint having a corresponding threaded section is then screw-connected to the joint pivot from the opposite direction, so that a rigid connection is brought about between the joint pivot of both joints and the articulated part arranged in the middle between these joints. A drawback of this other design known from the state of the art that must be stressed is especially the special shape of the joint pivot, which is related to a not inconsiderable production cost and thus must be considered to be cost-intensive.
The object of the present invention is to provide a two-joint arrangement of the generic type, which requires less work in terms of its production cost, can be easily mounted, and has an advantageous design in terms of the power flow within the two-joint arrangement. The objects are accomplished, in conjunction with the characterizing part of claims 1 and 5, by the technical teaching disclosed in these subordinate claims.
First of all, each of the two-joints of the two-joint arrangement has a joint housing each connected to a guide element and a bearing shell accommodated within the joint housing, in which a pivot part which is rigidly connected to the common articulated part is accommodated in a rotatable and pivotable manner.
According to the present invention, one pivot part of a joint is designed such that it has an opening running in the longitudinal axis of the pivot part, through which the pivot part of the other second joint penetrates with a screw bolt located on it, whereby a clamping nut is arranged on the free end opposite the pivot part of the other joint. The pivot part of the other joint is, as is already known from the state of the art, guided through an opening of the articulated part of the axle carrier arranged in the middle between the two joints.
A ball sleeve joint, which is available from the state of the art, may be used for that joint of the two-joint arrangement, in whose pivot part an opening is provided. Thus, for the two-joint arrangement containing special components, it is now only necessary to produce the specially designed pivot part of the other second joint. The mounting of the two-joint arrangement is extremely simple by means of simply putting together the joints used with the guide elements arranged thereon in the form of a steering rod and a steering tie rod, as well as the securing in position by means of a commercially available nut, such that another cost savings compared to the solutions known from the state of the art can be brought about.
It has proven to be especially advantageous if the pivot part of the other joint has an intermediate area of a cone-shaped design between the bearing area contained in the bearing shell and the screw bolt, which is contained in a corresponding, cone-shaped opening of the articulated part.
By means of the said cone connection between the pivot part and the articulated part, a highly rigid connection of both components can be brought about, whereby the rigidity primarily depends on the starting torque of the clamping nut placed on the screw bolt of the pivot part.
In addition, according to an advantageous improvement, the pivot part of the other joint has a tool mount for blocking the rotary movement of the pivot part about its longitudinal axis on its free end facing towards the bearing area. In this case, the tool mount may be designed as a screw slot recess or as a hexagon socket. By means of the measure described, a simple holding up for the tightening moment of the clamping nut is especially possible when screwing the components together.
The other way to accomplish the object according to the present invention provides for the two-joint arrangement for the articulated connection of guide elements, preferably of a motor vehicle steering linkage with a common articulated part, that both pivot parts of each joint have each an opening running in the longitudinal axis of the said pivot part, through which a screw bolt provided with a widened head area penetrates jointly, which screw bolt has, on its free end opposite the head area, a clamping nut detachably connected thereto.
Similar to the above-described solution variant 1, a ball sleeve joint known from the state of the art may be used for the ball-and-socket joints belonging to the two-joint arrangement, in the pivot parts of which are provided openings. Such joints are commercially available in different designs. For the embodiment of the two-joint arrangement according to the present invention, according to the second solution variant, only the special production of the screw bolt connecting the two ball-and-socket joints and the articulated part is necessary. This screw bolt has a simple design and thus is produced in a cost-favorable manner. The mounting of the two-joint arrangement according to the second solution variant can likewise be carried out in a simple manner, as was already explained in the description of the first solution example, by putting the components used, together, and screwing them together.
It may be especially advantageous that the screw bolt has, in the area of the pivot part openings, a thread-free partial area which has a slightly smaller external diameter than the respective pivot part openings. By means of this measure a sliding bearing is created between the pivot part of each ball-and-socket joint and the screw bolt, which has mounting-related advantages.
The openings in each pivot part of the ball-and-socket joints used are designed as through holes.
In addition, it has proven to be advantageous that the screw bolt has a cone-shaped design between the bolt areas contained in the openings of the pivot parts, whereby the cone-shaped intermediate area is contained in a corresponding, cone-shaped recess of the articulated part. By means of this measure, the screw bolt is secured in position without problems within the articulated part arranged in the middle between the ball-and-socket joints during the mounting, but may, during repairs, again be removed for replacing the ball-and-socket joints. Moreover, both possibilities for accomplishing the object described offer the guarantee that, in case of the wear of one of the two ball-and-socket joints used, the same may be replaced without the still intact, other ball-and-socket joint having to be additionally replaced as well.
In another advantageous embodiment of the present invention in accordance with claim 5, it may be expedient to pass the screw bolt through a cylindrical hole of the articulated part. A cavity designed in diameter as being larger than the actual hole, with which the pivot part of each ball-and-socket joint meshes after putting together the two-joint arrangement, may be arranged on both openings of the through hole. By means of this technical measure, a lateral shifting of the ball-and-socket joints onto the articulated part is prevented. A lateral shifting of the ball-and-socket joints may also be brought about by a bonding of the pivot parts on the corresponding surface of the said articulated part, whereby, within the framework of the structural design, the above-mentioned cavities in the articulated part may be omitted.